Google Earth

The Pacific Crest Trail around Muir Pass in Google Earth.

Google Earth is a free application that provides a remarkable aerial view of the entire Pacific Crest Trail. You can pan and zoom from campsite to water source, peak to valley. Features such as park and wildfire boundaries, roads, cloud cover and current snow pack totals can be displayed. With a little computer savvy, users can calculate elevation gain and loss, display elevation profiles, see which campsite will receive the first morning sun or what stars will be overhead for an exact time and place.

Google Earth becomes really great when you load layers like these

The MODIS Fire Detections KML layer shows fires along the PCT. Visit the main page here. This is satellite data that updates automatically. MODIS is 1 km resolution, so 1 km2 forms a cell. When a cell is ‘turned on’ (showing heat), there is a 50% chance there is fire within that cell. In other words, it’s also not very accurate.

The GeoMAC active fire perimeter KML shows large incidents, and their actual heat perimeter. This data is generally gathered by airplanes flying over the fires. Updates might not happen every day. While the GeoMAC layer is detailed, it might not be up to date. Nor does it show all fires. Generally, only the large, longer burning fires get airplane overflights and end up being shown in the GeoMAC layer.

Every day, the Terra satellite’s MODIS instrument takes a color picture of Earth. You can see it on our daily satellite image page or on NASA Worldview. If you click the camera icon in Worldview, you can export that day’s satellite image into a KML file and load it into Google Earth. So neat!

The Protected Areas Database shows land management boundaries, including USFS, NPS, BLM, reservation lands, private parcels and others. They are large files and will bog down your computer. Keep the layer off, zoom in, then open the layer. The previously linked .KMZ files incorporate the data from the official PAD database.

* Don’t trust your life to the information you gather from Google Earth.